This invention relates generally to mirrors curved in at least one plane to produce a virtual image having a specified angular magnification or demagnification with no angular distortion in the aforementioned plane and more particularly to such mirrors for use in vehicles.
The need and responsibility which a driver or navigator of a vehicle has for being aware of objects such as other vehicles in his surroundings are obvious. Various techniques, such as the use of rear-view mirrors for ground vehicles or the use of radar for aircraft and ships, have been devised to display or present an image of surrounding objects. Many of these techniques suffer from deficiencies such as gaps or distortions in the presentation of the image. For example, the conventional plane or flat rear-view mirror commonly used in automobiles does not adequately show objects to the side. The use of several mirrors, such as a rear-view mirror and two side-view mirrors, to remedy this shortcoming necessitates the dangerous procedure of looking from one mirror to another, often through a wide angle and often still with gaps in the view of the surroundings presented by the mirrors.
Spherical or other curved mirrors currently used present a wider but angularly distorted view of the surroundings. This angular distortion occurs whether the curved mirrors are used alone or are superposed on or used as "wings" (i.e., as adjoining end sections) for flat mirrors. Due to this angular distortion, the observer is provided with an inaccurate and unreliable representation of the spatial relationships between his or her vehicle and surrounding objects. Reliance on such an angularly distorted view of the surroundings could therefore be unsafe.
Even radar may not show the presence of very close objects as tragically witnessed by the crash of two airplanes approaching the same runway, one above the other, at the same time and in broad daylight at Moffett Field, Mountain View, California on Apr. 12, 1973. An appropriate mirror system with no angular distortion could have timely and accurately apprised the navigators of these airplanes of the danger.